New display item caching

Source/core/paint/ViewDisplayListTest.cpp

Index: Source/core/paint/ViewDisplayListTest.cpp
diff --git a/Source/core/paint/ViewDisplayListTest.cpp b/Source/core/paint/ViewDisplayListTest.cpp
index b095b4e06cbc4f6d77b82ebb3e5b2cab37aa7682..f62c85ad7ec6d25c9953a924884b7d731e2a0849 100644
--- a/Source/core/paint/ViewDisplayListTest.cpp
+++ b/Source/core/paint/ViewDisplayListTest.cpp
@@ -41,7 +41,6 @@ private:
     virtual void TearDown() override
     {
         RuntimeEnabledFeatures::setSlimmingPaintEnabled(false);
-        RuntimeEnabledFeatures::setSlimmingPaintDisplayItemCacheEnabled(false);
     }
 
     RenderView* m_renderView;
@@ -446,8 +445,6 @@ TEST_F(ViewDisplayListTest, ViewDisplayListTest_UpdateClip)
 
 TEST_F(ViewDisplayListTest, CachedDisplayItems)
 {
-    RuntimeEnabledFeatures::setSlimmingPaintDisplayItemCacheEnabled(true);
-
     setBodyInnerHTML("<div id='first'><div id='second'></div></div>");
     RenderLayerModelObject* firstRenderer = toRenderLayerModelObject(document().body()->firstChild()->renderer());
     RenderLayerModelObject* secondRenderer = toRenderLayerModelObject(document().body()->firstChild()->firstChild()->renderer());
@@ -519,5 +516,57 @@ TEST_F(ViewDisplayListTest, FullDocumentPaintingWithCaret)
         TestDisplayItem(divRenderer, DisplayItem::DrawingPaintPhaseCaret));
 }
 
+TEST_F(ViewDisplayListTest, ComplexUpdateSwapOrder)
+{
+    setBodyInnerHTML("<div id='container1'><div id='content1'></div></div>"
+        "<div id='container2'><div id='content2'></div></div>");
+    RenderObject* container1 = document().body()->firstChild()->renderer();
+    RenderObject* content1 = document().body()->firstChild()->firstChild()->renderer();
+    RenderObject* container2 = document().body()->firstChild()->nextSibling()->renderer();
+    RenderObject* content2 = document().body()->firstChild()->nextSibling()->firstChild()->renderer();
+    GraphicsContext context(nullptr, &rootDisplayItemList());
+
+    drawRect(&context, container1, PaintPhaseBlockBackground, FloatRect(100, 100, 100, 100));
+    drawRect(&context, content1, PaintPhaseBlockBackground, FloatRect(100, 100, 50, 200));
+    drawRect(&context, content1, PaintPhaseForeground, FloatRect(100, 100, 50, 200));
+    drawRect(&context, container1, PaintPhaseForeground, FloatRect(100, 100, 100, 100));
+    drawRect(&context, container2, PaintPhaseBlockBackground, FloatRect(100, 200, 100, 100));
+    drawRect(&context, content2, PaintPhaseBlockBackground, FloatRect(100, 200, 50, 200));
+    drawRect(&context, content2, PaintPhaseForeground, FloatRect(100, 200, 50, 200));
+    drawRect(&context, container2, PaintPhaseForeground, FloatRect(100, 200, 100, 100));
+    rootDisplayItemList().endNewPaints();
+
+    EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 8,
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content1, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content1, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content2, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content2, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseForeground));
+
+    rootDisplayItemList().invalidate(container1->displayItemClient());

[chrishtr, 2015/01/22 22:17:21]

Add a comment that this is simulating the situation when container1 gets e.g. a
z-index that is now greater than container2.

[Xianzhu, 2015/01/22 23:50:59]

Done.

+    drawRect(&context, container2, PaintPhaseBlockBackground, FloatRect(100, 200, 100, 100));
+    drawRect(&context, content2, PaintPhaseBlockBackground, FloatRect(100, 200, 50, 200));
+    drawRect(&context, content2, PaintPhaseForeground, FloatRect(100, 200, 50, 200));
+    drawRect(&context, container2, PaintPhaseForeground, FloatRect(100, 200, 100, 100));
+    drawRect(&context, container1, PaintPhaseBlockBackground, FloatRect(100, 100, 100, 100));
+    drawRect(&context, content1, PaintPhaseBlockBackground, FloatRect(100, 100, 50, 200));
+    drawRect(&context, content1, PaintPhaseForeground, FloatRect(100, 100, 50, 200));
+    drawRect(&context, container1, PaintPhaseForeground, FloatRect(100, 100, 100, 100));
+    rootDisplayItemList().endNewPaints();
+
+    EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 8,
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content2, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content2, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content1, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content1, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseForeground));
+}
+
 } // anonymous namespace
 } // namespace blink